General question about clutch fethering

[cpayne]

Just finished MSF basic class at Fort Lee, so I can ride on base.

e used Susuki 250. Big difference from 1150. During the entire class we were abusing the clutch and brakes. Never smelled clutch on any of them. I sometimes smell a little on my bike after a ride with very little feathering taking place.

I asked the instructor if this was normal. He said he has been teaching for years and has never had a clutch go out on him. only changed front pads.

He did mention that in the advanced riders course a guy with a big cruiser burned his out after 10 minutes of doing what we did for two days. I assume something was wrong with his clutch from the get go.

 

What are your experiences with BMW bikes as feathering (control) is a major technique in Motorcycle riding.

 

[Penforhire]

I use more care with dry single plate clutches (such as my RT's) than with wet multiplates. It will not stand up to as much abuse. It doesn't mean I don't feather it for control but more often I'm conscious to lock it up sooner and slip it less than I did with wet clutches.

[dirtrider]

Evening cpayne

 

The clutch on your bike is what's known as a dry clutch. That means it is not oil cooled & doesn't run in oil.

 

The clutch on your motorcycle is a rather large clutch disk (about the size of a VW beetle) so you can feather it a bit at low engine RPM's if needed. High RPM slippage will kill your clutch in a hurry though as that make tremendous heat.

 

You really do need to be a bit careful with it as you can fry it if you slip it very long with raised engine RPM's.

 

If you are smelling the clutch after usage you are probably using a bit too much feathering at too high of an engine RPM during the feathering.

 

If you know what you are doing the BMW dry clutch can be slipped or feathered a fair amount without damage but on the BMW dry clutch there is a very fine line between light feathering & destructive slipping.

 

On my BMW GS I abuse the heck out of that clutch when off-roading in deep sand or real tight narrow trails but never at raised engine RPM (that means high engine torque) & not for long. Haven't fried a clutch yet.

 

I don't use a long term high rev feathering though-- it is more of a low engine RPM thing while pulsing of the clutch lever (continuously pulling the clutch lever slightly in & out at the engagement point).

 

 

 

[cpayne]

Thanks for the detailed information. This explains quite a bit. I haven't had the bike very long and I didn't know the difference. I may have been a little aggressive the first couple of times i rode the bike. Hence the smell.

I went for long(to me) rides yesterday and today and feathered quite a bit in and around intersections lights etc... No smells of clutch!

 

Seems that wet may be more reliable or durable? If so why would manufacturers use dry clutches?

 

 

[bgf50]

I've only smelled my clutch burning twice. Once when I was starting out on a steep hill with my wife on the back ( I almost always ride solo) and once when I was riding with my brother. He has a LOUD cruiser and when I was behind him I couldn't hear my bike at all and I revved the engine too much. I really wasn't even sure my bike hadn't stalled because his bike was so loud.

 

Bill

2012 RT

09 KLR

[Rex R]

This issue has been covered several times on this forum (and others.) You can search for related threads if you would like to find more info and other opinions.

 

The info I'm posting below is a cut-and-paste from a brochure for the 1200RTP. It backs up what Dirt and other posters say and further explains why you have to keep the revs low in the grey zone and why you might not need to slip the clutch at all during maneuvers that would require other bikes to stay in the friction zone.

 

 

What’s Up With BMW’s Clutch?

BMW utilizes a different clutch system than some of our competitors. BMW’s clutch is a hydraulic (self-adjusting) single-plate dry clutch as used in cars and trucks … well proven for long life. Our competitors utilize a multi-plate wet clutch, which runs in an oil bath.

The primary difference between the two designs is that the dry clutch operates at the end of the engine crankshaft before the primary gear reduction. The wet clutch design operates after the primary gear reduction. Meaning, that for a given RPM on a dry clutch design, the same RPM on a wet clutch design will be turning that wet clutch surface approximately half as fast (feet-per-second at the plate surface). Conversely, if you have been trained to ride a wet clutch motor, you will need to greatly reduce the RPM on the dry clutch motor to keep from over-heating it. How long would any wet clutch last if you grey-area slipped that clutch at 5,000 rpm?

Furthermore, the unique BMW opposed-twin engine design enables the motor to pull itself at idle with no throttle in either first or second gear. Consequently, the motor works best at slow rpm grey area operation below 2,000 rpm. Most fleets that have received indoctrination training have experienced no clutch issues and are seeing clutch life as high as 60,000 miles! Lastly, the BMW warranty covers the clutch for wear in the first 12 months while your officers acclimate to the motor!

 

 

 

 

 

CHPs (who are the biggest user and therefore the most experienced with these bikes in this country) train their cops to perform slow speed maneuvers without the use of the rear brake (using only clutch, throttle control and perhaps counter-balancing ) The reason being dragging the rear brake, although it tends to stabilize the bike and makes it easier to ride the training/cone courses, also forces you to raise the revs putting more wear on the clutch and input spline shaft.

 

Good luck with your new wheels, and thank you for your service.

[cpayne]

This issue has been covered several times on this forum (and others.) You can search for related threads if you would like to find more info and other opinions.

 

The info I'm posting below is a cut-and-paste from a brochure for the 1200RTP. It backs up what Dirt and other posters say and further explains why you have to keep the revs low in the grey zone and why you might not need to slip the clutch at all during maneuvers that would require other bikes to stay in the friction zone.

 

 

What’s Up With BMW’s Clutch?

BMW utilizes a different clutch system than some of our competitors. BMW’s clutch is a hydraulic (self-adjusting) single-plate dry clutch as used in cars and trucks … well proven for long life. Our competitors utilize a multi-plate wet clutch, which runs in an oil bath.

The primary difference between the two designs is that the dry clutch operates at the end of the engine crankshaft before the primary gear reduction. The wet clutch design operates after the primary gear reduction. Meaning, that for a given RPM on a dry clutch design, the same RPM on a wet clutch design will be turning that wet clutch surface approximately half as fast (feet-per-second at the plate surface). Conversely, if you have been trained to ride a wet clutch motor, you will need to greatly reduce the RPM on the dry clutch motor to keep from over-heating it. How long would any wet clutch last if you grey-area slipped that clutch at 5,000 rpm?

Furthermore, the unique BMW opposed-twin engine design enables the motor to pull itself at idle with no throttle in either first or second gear. Consequently, the motor works best at slow rpm grey area operation below 2,000 rpm. Most fleets that have received indoctrination training have experienced no clutch issues and are seeing clutch life as high as 60,000 miles! Lastly, the BMW warranty covers the clutch for wear in the first 12 months while your officers acclimate to the motor!

 

 

 

 

 

CHPs (who are the biggest user and therefore the most experienced with these bikes in this country) train their cops to perform slow speed maneuvers without the use of the rear brake (using only clutch, throttle control and perhaps counter-balancing ) The reason being dragging the rear brake, although it tends to stabilize the bike and makes it easier to ride the training/cone courses, also forces you to raise the revs putting more wear on the clutch and input spline shaft.

 

Good luck with your new wheels, and thank you for your service.

More great information. Thanks and I'll try to find some of the posts you mentioned.

[lkchris]

Boy, does this miss the point.

 

The real point is that driving around a parking lot has so very little to do with motorcycling in the real world and is of course the fatal flaw with MSF.

 

Granted "political correctness" dictates that MSF isn't going to be able to get state funding to give you race track experience, but that remains indeed the best sort of motorcycle training.

 

Now that you're past MSF, clutch feathering is irrelevant for the most part. You can start shutting your motor off with the ignition key, too.

[Huzband]

That is so wrong on so many points, I hardly know where to begin. But I'll try.

 

1; Parking lots are a great place to work on the basics, ie, accelerating, shifting, clutch work, basic manuvering...

 

2: Track days don't teach beginners how to ride, they teach riders how to ride better.

 

3: Clutch feathering...ever try to turn a moto around in a tight space, or negotiate a tight corner, without paddling like a duck?

 

lkchris, I think YOU miss the point.

[David13]

Kent

I don't think I'm being politically correct by saying I disagree.

Anyone can make the motorcycle go fast. What takes skill, and most importantly control, is to make it go slow.

I do agree. Shut the bike off with the ignition key.

dc

[dirtrider]

Evening Danny, David

 

I definitely agree with both of you guys. I've been riding motorcycles for over 50 years (way before a motorcycle license was even needed) so have taken a lot of specialized motorcycle training courses over the years. Lots of track time in my younger days & some specialized training.

 

 

By far the hardest training I ever took on a motorcycle was in a large parking lot. That was a full blown police motor course. If you ever tried to ride a Harley dresser over a 4x6 at speed, or across a deep cement trench on a narrow board, or up & down a steep set of cement steps you will know what I'm talking about.

 

Few weekend track riders can do a feet up leaned over full lock "U" turn in 16' wide road with a passenger on the back. I know two motorcycle safety instructors that can do that back to back in a figure 8 & they learned that in a parking lot.

 

[Quinn]

No matter how fast you can go, eventually you'll have to go slow.

 

The MSF course prepares you to learn to ride a motorcycle. I wish they'd added some information on how to pick out a parking place and which way to be facing.

 

----

 

 

[lkchris]

Anyone can make the motorcycle go fast.

 

What do they do when they come to a curve going fast? We have lots of them where I ride.

 

You can get hurt in this situation. Falling over in a parking lot is only embarassing.

 

I know myself I can't steer a Harley around Indianapolis Motor Speedway standing on the seat. But, it's cute. It's irrelevant if parking lot riding is "difficult."

 

Nice article in current BMW Motorcycle Magazine, "Track Training and Coaching" by Keith Code. Get it. Learn something useful.

[tallman]

Anyone can make the motorcycle go fast.

 

What do they do when they come to a curve going fast? We have lots of them where I ride.

 

You can get hurt in this situation. Falling over in a parking lot is only embarassing.

 

I know myself I can't steer a Harley around Indianapolis Motor Speedway standing on the seat. But, it's cute. It's irrelevant if parking lot riding is "difficult."

 

Nice article in current BMW Motorcycle Magazine, "Track Training and Coaching" by Keith Code. Get it. Learn something useful.

 

 

 

Wow.

And to think after all these years I finally read something useful.

 

[4wheeldog]

I taught numerous folks to ride before the advent of MSF. I have also taught lots of kids to drive. And even some adults to operate a manual transmission. And more than a few to operate a forklift.

An axiom for my lessons is that you teach one thing at a time, before adding them together. And every skill is learned at the lowest speed possible, and speed in not increased until mastery is evident at very low speeds. Not always easy, but it does give one confidence, and not the kind that is undeserved.

[FlyingFinn]

Good thing we don't have JM here on BMWST. If we did, that's where this thread would be heading.

Clutch feathering is problem because "politically correct" government funded MSF class teaches slow speed bike control instead of how to race down the track at max speed... Yeah.

 

--

Mikko

[CoarsegoldKid]

Feathering a dry clutch on a loaded early R1200RT on flat ground at slow speed should not have ill effects. But you can fry them quickly on inclines. Clutches are expensive repairs. GS models have lower gearing and do better.

[cpayne]

The MSF basic course is mandatory for Motorcycle riders in uniform. It was initiated when someone realized riders (mostly sport bike riders) were getting killed or injured with great frequency.

Lots of "Hold my beer and watch this." scenarios seemed to me a factor.

This is the typical government/ armed services response.

Anytime someones safety has the potential to be compromised. Some new mandatory training is implemented Service wide.

http://www.npr.org/templates/story/story.php?storyId=102990179

 

The basic course assumes no riding experience at all and baby steps you through into riding. In taking the course I learned that I had many bad habits. Practicing sudden stopping and gearing down to get out of the way. Scanning ahead, swerving and slow controlled turns.

 

These techniques really helped me feel more confident.

I have the Enhanced riders course coming up. Mandatory for touring and cruisers within 1 year of the basic course. In the case of sport bike a mandatory sport bike class is offered.

 

This is all implemented to prevent non combat related deaths and I'm glad they make us take it.

 

As the article points out Track days are now being implemented to

allow fast riding in a controlled environment.

[BailyD]

They are both important....higher speed and lower speed riding, in addition to "street survival" riding. Dealing with the endless number of ways to get wiped out in the less than controlled atmosphere of a parking lot or race track.

[Kathy R]

Boy, does this miss the point.

 

That's funny, seeing as how it's his thread.

 

The real point MY point is that driving around a parking lot has so very little to do with motorcycling in the real world and is of course the fatal flaw with MSF.

 

I had to fix that for you.

 

Granted "political correctness" dictates that MSF isn't going to be able to get state funding to give you race track experience, but that remains indeed the best sort of motorcycle training.

 

I don't know about you, but I didn't come out of the womb knowing how to ride a motorcycle. MSF was a great starting point.

 

As for the topic of feathering the clutch, I appreciate the insight offered by others here. I learned something. Good topic, cpayne.

 

 

 

 

 

 

 

[motorman587]

That is so wrong on so many points, I hardly know where to begin. But I'll try.

 

1; Parking lots are a great place to work on the basics, ie, accelerating, shifting, clutch work, basic manuvering...

 

2: Track days don't teach beginners how to ride, they teach riders how to ride better.

 

3: Clutch feathering...ever try to turn a moto around in a tight space, or negotiate a tight corner, without paddling like a duck?

 

lkchris, I think YOU miss the point.

 

Well said Sir!!! Of all the posts I like this one, because you have to #1 first to go to #2.

 

My. $.03, when you smell the clutch that means you used too much rear brake with too much clutch. RTs are great motorcycle for slow speeds, you can pretty much idle through police cone course with clutch all the way out or little bit of feathering. Like some have posted, no need for rear brake.

[racer7]

Back on clutch design stuff...

The dry clutch is also a bit more prone to making stink when new and being broken in- the same as new brakes often make a lot of dust in their first few miles while they're getting bedded...

So if you're new to a dry clutch and have a new BMW you might have two issues going on- the new clutch and the need for the rider to get used to the friction point characteristics of the bike.

Except for the very most extreme hill starts on a loaded to the limit bike you shouldn't notice any smells after breakin and getting used to the bike. Unles you mistake it for a drag racer...

[Peter Parts]

Wet and dry clutches differ in a whole bunch of ways. The problem is that it is pretty wacky to use internal combustion engines on vehicles, except all the alternatives in 1920 seemed worse.

 

Of course it is stupid to connect a motor with zero torque at stall to a transmission using an all-or-nothing dry clutch. Of course, some might say it is just as stupid to have a clutch in an oil bath.

 

But in practice, BWM clutches last almost forever unless you are abusing them. "Almost forever" is certainly far longer than the 60,000 miles quoted in that early post (just to pick on one silly thing in that quote).

 

With experience and if you don't live in hilly San Francisco, you get real good at quick use of the clutch and barely need to rub them.

 

Ben

[KLC]

I teach CBT( Compulsory Basic Training) for new motorcyclists and the hardest skill for any motorcyclist to learn is the slalom through the cones,U Turns from kerb to kerb in 6.5 metres and the figure eight turns. They also are taught to ride at less than a normal walking pace. They have to master these skills before being allowed to ride on the road. Takes a lot of practice to get it right. As i was told years ago any fool can ride a bike fast it takes skills and practice to ride slowly.

[Dave_zoom_zoom]

As i was told years ago any fool can ride a bike fast it takes skills and practice to ride slowly or ride a bike fast and skillfully.

 

There, I fixed it for you! (maybe you won't like it)

 

Dave

 

[Ken H.]

There is another thought/approach on this with the BMW dry clutches, it’s been talked about here and other places, but I’ll try to summarize...

 

The term “feathering” in common usage typically means holding the clutch lever so the clutch plates (input engine side vs. output drive train side) are only partially spinning at the same RPM. There is slippage between them going on as same input/output RPM would result in the motorbike moving faster than desired. This is indeed quite hard on BMW dry clutches.

 

But there is another more effective, and much less abusive, approach and that’s what’s oten called pulsing the clutch. In effect moving it in and out of from just before engagement to just starting to engage, rather rapidly to accomplish the same speed control. In effect engaging and disengaging the clutch many many multiple times. Depending on the maneuver, maybe 2 or 3 times a second even. So small amounts of movement with the clutch lever in and out, in and out that to the casual observer of your hand; they might not even notice you are doing it at all. The effective total % of time the clutch plates are slipping against each other as a result is dramatically less.

 

And there is the bonus of once mastered; it really does give you much finer bike control. You quickly learn how much subconsciously to ‘pulse’, or maybe modulate is a better word, for just the amount of additional movement of the bike you want to add (or delete by allowing micro-coast down of your speed). It’s much easier to control than constantly searching for that elusive (and always changing) amount of feathering/slipping needed for the moment at hand.